1. Field of the Invention
The invention relates to a B pillar for a motor vehicle, produced as a hot-worked and press-hardened component composed of a hardenable steel alloy, and more particularly, to a produced hot-worked and press-hardened component composed of a hardenable steel alloy.
2. Description of the Related Art
Some motor vehicle components can be produced by hot-stamping and press hardening. For this purpose, a blank composed of a hardenable steel alloy, for example, a manganese-boron steel, is austenitized at least regionally, is deformed in the hot state, and is subsequently rapidly cooled such that quench hardening, also referred to as press hardening, occurs. In this way, it is possible to realize tensile strength values of over 1400 MPa.
It is thus possible to produce motor vehicle structural components, in particular B pillars, roof frames, beams, sills and crossmembers, which have high strength characteristics. The stability of the motor vehicle body in the event of an accident thus remains ensured. At the same time, it is made possible to use smaller wall thicknesses, such that the weight of the motor vehicle body can be reduced, and thus also the CO2 emissions are minimized.
A generic motor vehicle pillar, in particular B pillar, is disclosed in EP 2 209 696 B1. A lower length section is formed with a relatively soft material structure in relation to an upper length section. This offers the advantage that, in the event of a side-on collision, the motor vehicle B pillar deforms in targeted fashion, and dissipates energy in the process, but complete crack formation or, for example, a breakaway from the attached sill is prevented.
US 2012/0319431 A1 discloses a motor vehicle pillar which, in cross section, is in the form of a hat-shaped profile. Flanges are of soft form over a relatively large length section in their longitudinal direction, wherein the rest of the cross section has a hard material structure or transition region.
DE 10 2014 112 740 A1 discloses a motor vehicle pillar which, in the lower region in a longitudinal direction, has strips with mutually different strength. Here, a hard strip is coupled to the sill. The hard strip does not extend beyond a fold edge.